Many of us have broadband with usage restrictions like an 8GB download limit per month when downloaded in peak periods (off peak is unrestricted between 00:00 and 06:00). So for those with restrictions like this will often run backups nightly to run between this time.
Currently I have written a wrapper script to rsync called lrsync that accepts an option of --end-time. This option takes a timestamp that will force rsync to terminate when the current time exceeds the time represented by the timestamp. For example, running lrsync at midnight with the following option:
lrsync --end-time $(( $(date +%s) + 21600 ))
...will force rsync to terminate at 6 am. This ensures no data is sent during the peak periods to avoid using up the data transfer limit imposed by the ISP.
It would be nice for this feature to be built into rsync since I think it would be useful for others like myself, with broadband usage restrictions.